You may have seen the online kerfuffle a few weeks ago about a study that was released recently that indicated that there was no evidence that masks work against respiratory illnesses (see Bret Stephen’s awful ideologically driven piece in the NY Times for instance). As many experts said at the time, that’s not what the review of the studies actually meant and the organization responsible recently apologized and clarified the review’s assertions.
In a typically well-argued and well-researched piece for the NY Times, Zeynep Tufekci explains what the review actually shows and why the science is clear that masks do work.
Scientists routinely use other kinds of data besides randomized reviews, including lab studies, natural experiments, real-life data and observational studies. All these should be taken into account to evaluate masks.
Lab studies, many of which were done during the pandemic, show that masks, particularly N95 respirators, can block viral particles. Linsey Marr, an aerosol scientist who has long studied airborne viral transmission, told me even cloth masks that fit well and use appropriate materials can help.
Real-life data can be complicated by variables that aren’t controlled for, but it’s worth examining even if studying it isn’t conclusive.
Japan, which emphasized wearing masks and mitigating airborne transmission, had a remarkably low death rate in 2020 even though it did not have any shutdowns and rarely tested and traced widely outside of clusters.
David Lazer, a political scientist at Northeastern University, calculated that before vaccines were available, U.S. states without mask mandates had 30 percent higher Covid death rates than those with mandates.
Randomized trials are difficult to do with masks and are not the only way to scientifically prove something. I’m hoping for an update that the entire premise of that Stephens piece is incorrect and will be removed from the Times’ website, but I don’t think it’s going to happen.